Control device for internal combustion engine with cylinder deactivation

Abstract

A control device for an internal combustion engine is provided. The internal combustion engine is configured to perform switching between an all-cylinder operation and a partial cylinder operation. The internal combustion engine includes a temperature regulator. The temperature regulator is configured to separately regulate the temperature of an operating cylinder and the temperature of a paused cylinder. The operating cylinder is a cylinder that operates during the partial cylinder operation. The paused cylinder is a cylinder that is paused during the partial cylinder operation. The control device includes an electronic control unit. The electronic control unit is configured to (i) calculate a temperature difference between the operating cylinder and the paused cylinder during the partial cylinder operation, and (ii) control the temperature regulator such that the temperature difference becomes equal to or smaller than a predetermined threshold.

The invention claimed is: 
     
       1. A control device for an internal combustion engine, the internal combustion engine configured to perform switching between an all-cylinder operation and a partial cylinder operation, the internal combustion engine including a temperature regulator, the temperature regulator being configured to separately regulate the temperature of an operating cylinder and the temperature of a paused cylinder, the operating cylinder being a cylinder that operates during the partial cylinder operation, and the paused cylinder being a cylinder that is paused during the partial cylinder operation, the control device comprising:
 an electronic control unit configured to: 
 switch between the all-cylinder operation and the partial cylinder operation; 
 calculate a temperature difference between the operating cylinder and the paused cylinder during the partial cylinder operation; and 
 control the temperature regulator such that the temperature difference becomes equal to or smaller than a predetermined threshold, wherein: 
 the temperature regulator includes a cooling water supply channel that is divided upstream of the operating cylinder and the paused cylinder into a first water conduction channel and a second water conduction channel; 
 the first water conduction channel is configured to conduct a cooling water to the operating cylinder, the second water conduction channel is configured to conduct the cooling water to the paused cylinder; 
 the temperature regulator is configured to separately regulate an amount of water conduction of the first water conduction channel and an amount of water conduction of the second water conduction channel; 
 the electronic control unit is configured to control the temperature regulator such that the temperature regulator conducts a cooling water only to the operating cylinder when the temperature difference is equal to or smaller than the predetermined threshold; and 
 the electronic control unit is configured to control the temperature regulator such that the temperature regulator conducts the cooling water to the operating cylinder and the paused cylinder when the temperature difference is larger than the predetermined threshold. 
 
     
     
       2. The control device according to  claim 1 , wherein the internal combustion engine includes a first temperature sensor that detects the temperature of the operating cylinder and a second temperature sensor that detects the temperature of the paused cylinder, and the electronic control unit is configured to calculate the temperature difference on the basis of detection values of the first temperature sensor and the second temperature sensor. 
     
     
       3. The control device according to  claim 1 , wherein the electronic control unit is configured to calculate the temperature difference on the basis of the output history of the internal combustion engine. 
     
     
       4. The control device according to  claim 1 , wherein the operating cylinder is a plurality of the operating cylinders. 
     
     
       5. The control device according to  claim 1 , wherein the paused cylinder is a plurality of the paused cylinders.